Monoazo-dyestuffs



Patented Apr, 25, 195W iTED; STATES PATENT OFFICE MONOAZO-DYESTUFFS land, a Swiss firm No Drawing. Application September 4, 1946, Se-

rial No. 694,830. In Switzerland October 4,

4 Claims.

According to this invention valuable new monoazo-dyestuffs are made by coupling a sulfonic acid of Z-aminonaphthalene or a nuclear substitution product thereof in an acid medium with a diazo-compound of an amine of the genformula:

in which one R represents phenyl and the other R represents phenyl or benzyl, the phenyl nuclei of which radicals may contain further substituents, for example, an alkyl, alkoxy or carboxyl group, or a halogen atom, but not nitro groups or sulfonic acid ester or sulfon-amido groups.

As alkyl or alkoxy groups there can be used especially the methyl and the ethyl groups or the methoxy and the ethoxy groups. Among the halogen substituents mention is to be made of bromine, for example, especially of chlorine. Furthermore, several similar or diiierent substituents may be present in the molecule.

As starting materials for making the new dyestuffs there may be mentioned the following amines: 4-amino-l:l-diphenyl ether, 2:4-di chloro-4-amino-1:1-diphenylether, 3- or 4- amino-1:l-phenyl benzyl ether, 5-amino-2- methy1-l:1-phenyl benzyl ether, 5-bromo-3- amino2-methyl-1:l-phenyl benzyl ether, 4- chloro-2-amino-1:1-phenyl benzyl ether and the like.

Especially valuable are the dyestuffs derived from diazo compounds of the amines of the aforesaid kind of which the amino group occupies a 2-position relatively to the ether bridge.

Among these dyestuffs special mention is to be 1 made of those which are derived from Z-amino- 1:1 -diphenylethers substituted by halogen atoms, for example chlorine atoms. In these ethers one or several halogen atoms may be present in the molecule, for example, in 4-, 2- and/or 4-position. Examples of such compounds are:

4-ch1oro-2-amino-lrl'-diphenyl ether, 4-ch1oro-2-amino 3 methyl 1:1 diphenyl ether, 4:4-dich1oro-2-amino-l:1-diphenyl ether, 4 2'-dichloro-2-amino-l :1 -diphenyl ether and the like.

The aminodiphenyl ethers can, be made for example by the reaction of a halogen-nitrobenzene which contains a reactive halogen atom with an alkali salt of a phenol followed by reduction of the nitro group to an amino group; and the amino phenyl. benzyl ethers, for example, by the reaction of a benzyl halide with an alkali salt of a phenol, the components being so chosen that the reaction product contains a nitro group, the latter group being reduced after the reaction to an amino group.

As coupling components for making the new dyestufis there are especially suitable :Z-aminonaphthalene sulfonic acids which contain a hydroxyl group as a nuclear substituent, for example, 2 amino 8-hydroxynaphthalene6-sulfonic acid, 2-amino-5-hydroxynaphthalene-7- sulfonic acid, 2-amino-3-hydroxynaphthalene-'7- sulfonic acid, 2-aminc-7-hydroxynaphthalene-4- sulfonic acid, and the like; but also, for example, 2-aminonaphthalene-fi-sulfonic acid, IZ-aminona-phthalene-Y-sulfonic acid, 2-aminonaptha-- lene-3:6-disulfonic acid, Z-aminonaphthalene- 5 :7-disulfonic acid and the like.

The new dyestuffs correspond to the general formula in which one of the radicals R and R represents phenyl and the other represents phenyl or benzyl, and in which the aminonaphthalene residue contains as substituents at least one sulfo group and if desiredv further substituents, for example, hydroxyl groups.

The following examples illustrate the invention, the parts being by weight:

Example 1 25.4 parts of 2':4-dichloro-2-amino-lzl-diphenyl ether are diazotized in the usual manner with parts of hydrochloric acid of per cent. strength and 6.9 parts of sodium nitrite in 200. parts 0t water at 05 C. 23.9 partsof 2- amino 8 hydroxynaphthalene 6 sulfonic acid are dissolved in 300 parts of water with 5.5. parts. of sodium carbonate, and the clear diazonium solution is run in at 0-5 C. The

whole is stirred for one hour at -8 C., and then a solution of 30 parts of crystalline sodium acetate in '75 parts of water is introduced dropwise in the course of one hour. After stirring for 6 hours at -12 C. the diazonium compound disappears. The whole is then slowly warmed to 40-50 C., and the dyestuff so formed is separated by filtration after the addition of parts of sodium chloride. When dry the dyestufi which corresponds in the free acid state to the formula is a dark red powder which dissolves in water with a red coloration and dyes wool from an acid bath clear bluish red tints having good properties of wet fastness and an excellent fastness to light.

A dyestuif having similar properties is obtained by using in this example, instead of 1 0- 2-arnino-l:1 -diphenyl ether, 4:4--dichloro-2- amino-1 l-diphcnyl ether.

Example 2 25.4 parts of 2:4-dich1oro-2-amino-1:1'-diphenyl ether are diazotized with parts of hydrochloric acid of per cent. strength and 6.9 parts of sodium nitrite in 200 parts of Water at '0-5 C. The clear diazonium solution is run at (3-5 0. into a neutral solution of 22.3 parts of 2- aminonaphthalene6-Sulf0-nic acid in 300 parts of water. The coupling mixture is maintained at a weakly mineral acid reaction by introducing a 10 per cent. solution of sodium carbonate dropwise. After 12 hours the temperature is allowed to rise of 10-15 (3., and the whole is stirred for a further 12 hours at the same temperature. By the end of this period the diazonium compound disappears. The whole is then warmed to -50 0., a sufiicient quantity of sodium carbonate is added to render the solution distinctly alkaline, and the dyestufi so formed which corresponds in the free acid state to the formula HaN Ol BOsH is separated by filtration after the addition of 30 parts of sodium chloride.

When dry the dyestuii is a red powder which dyes wool from an acid bath clear orange-red tints having good properties of wet fastness and fastness to light.

Dyestuffs having similar properties are obtained by using in this example, instead of i-dichloro- 4 2-amino-1:l' diphenyl ether, 4:4 dichloro-2- amino-1:1-diphenyl ether, 2-c'hloro-2-amino- 1:1'-diphenyl ether or 4-chloro-2-amino-1:1'-diphenyl ether.

Example 3 0.2 part of the dyestuff obtained as described in the first paragraph of Example 1 is dissolved in 400 parts of water, 1 part of crystalline sodium sulfate is added to the dyebath, and 10 parts of wool are entered at 40-50 C. 0.3 part of acetic acid is then added, the bath is slowly brought to a gentle boil in the course of hour, and dyeing is carried on for hour at that temperature. After rinsing and drying a bluish-red dyeing is obtained, which has good properties 0:. fastness, more especially a very good fastness to light.

Example 4 HzN | S O aH wherein one X stands for hydrogen and the other X for chlorine, and Y stands for a member of the group consisting of H and OH.

2. The dyestufi which in the free acid state corresponds to the formula 3. The dyestuif which in the free acid state corresponds to the formula Hal? SOzH

5 4. The dyestuff which in the free acid state corresponds to the formula REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS 5 Number Number G1 SOIH FRIEDRICH FELIX. WILLY MUELLER.

Disclaimer 2,505,533.Friedrieh Felia: and Willy Mueller, Basel, Switzerland, MONOAZO-DYE- STUFFS. Patent dated Apr. 25, 1950. Disclaimer filed July 31, 1950, by the assignee, Oiba Limited. Hereb enters this disclaimer to claim 1 of said patent.

5' [Q i'icial Gazette, Sept. 5, 1950.] 

1. A MONOAZO DYESTUFF WHICH IN THE FREE STATE CORRESPONDS TO THE FORMULA 